The invention relates to a positioning arrangement for moving an object that is to be positioned, with at least two electric motors for moving the object that is to be positioned, wherein at least two electric motors are provided in each case for each positioning axis, with an actuation element for each positioning direction with which an adjustment request can be triggered, and with a control circuit to evaluate the adjustment requests and to control the electric motors.
Positioning arrangements of this type are used if, for example, wide objects that are to be positioned have to be moved but are not sufficiently rigid over their width to be driven by an electric motor. An awning, for example, which consists of a wide panel of material and is provided with electric motors on both sides to extend or retract it.
A further example of a positioning arrangement of this type is the drive unit for a convertible vehicle top, wherein an electric motor with which the top can be opened or closed is arranged on each side of the top.
A common feature of each of these applications is that it must always be ensured that the two electric motors are moved absolutely synchronously. If one of the motors starts or stops earlier, this results in a twisting of the object that is to be positioned. The object that is to be positioned can be blocked, damaged or destroyed as a result.
The synchronous control is performed in the prior art by a central control circuit to which the actuation elements and the electric motors are connected. The control circuit evaluates the switching commands of the actuation elements, checks their validity and then controls the electric motors simultaneously and synchronously. It is thus ensured, for example, that one motor is not moved in one positioning direction while the other is moved in the other positioning direction. Similarly, it can thereby be ensured that the electric motors move at the same speed and coordinated positioning paths are travelled.
Multi-phase brushless DC motors (BLDC motors) are increasingly used in modern positioning arrangements. To control multi-phase electric motors of this type, the control circuit additionally requires a motor driver which transforms the DC voltage into the phase alternating voltages.
These require a cable connection to the control circuit for each motor phase, so that a very large number of lines must be installed along with the cable connections to the actuation elements. As a result, the proneness to faults and installation cost are very high.
Many BLDC motors also exist which are equipped with their own motor drivers which are activated via bus systems. These BLDC motors require no motor drivers in the central control unit for the synchronous control. However, this means that the available control circuits have unnecessary functional units, thereby incurring additional costs.